FCC Chairman Julius Genachowski said Friday he'll be stepping down "in the coming weeks" before his term expires at the end of June.

He has held the top post at the Federal Communications Commission since 2009 after being appointed by President Obama, his law school classmate at Harvard. The FCC is the nation's key regulator of radio, TV, wireless, satellite and cable communications.

"I'm proud that we focused the agency on broadband and extending high speed Internet to everyone everywhere, wired and wireless and we have a revitalized agency that's focused on this vital mission of unleashing the benefits of high speed internet for all Americans," Genachowski told USA TODAY in a telephone interview after addressing his staff Friday morning.

"Three years ago, the U.S. was on the doorstep of a duopoly when it came to mobile competition," he said. "That would have been bad news for America's innovation economy and American consumers. Today we are seeing revitalized mobile competitors in the U.S. and strengthening competition and trend lines moving in a positive direction. That is good for innovation and good for consumers."

Since the start of Obama's second term in office, the FCC has been expecting turnover. The announcement comes two days after Commissioner Robert McDowell said he also will step down, leaving two vacant positions in the five-member panel.

Genachowski's term overlapped with a period of national expansion of broadband Internet and an unprecedented rate of innovation in mobile technology that fueled the demand for tablets and smartphones. Increasing competition in the wireless industry and continuing to broaden the reach of broadband Internet service to rural areas remained high priority areas for the 50-year old lawyer.

Under Genachowski, the U.S. "expanded high-speed Internet access, fueled growth in the mobile sector, and continued to protect the open Internet as a platform for entrepreneurship and free speech," President Obama said in a statement.

Consumer Electronics Association CEO Gary Shapiro dubbed Genachowski as "the Spectrum Chairman." In a statement, Shapiro said that "consumers and industry alike will benefit for years to come thanks to Genachowski's service at the FCC."

In listing the key developments under his watch, the FCC said nearly $250 billion in private capital has been invested in U.S. wired and wireless broadband networks since 2009.

"There has been more private investment in the information and communications technology sector than in any other sector of the U.S. economy," the agency said in a statement. "More fiber has been laid in the U.S. in each of the last two years than in any year since 2000."

Information Technology and Innovation Foundation President Rob Atkinson concurred, noting more than 96% of the U.S. has access to wired broadband -- and 82% of U.S. homes have access to a broadband network with speeds of 100 Megabits per second -- plus, the U.S. leads in adoption of 4G LTE mobile broadband.

"During his tenure, the U.S. has made major advances in the speed of our broadband networks and expanded the deployment of next generation broadband technology," Atkinson said in a statement.

Annual investment in U.S. wireless networks grew more than 40% to $30 billion between 2009 and 2012, it said. Investment in European wireless networks has been flat since 2009, and it's up only 4% in Asia.

In anticipation of Genachowski's resignation, public interest group Public Knowledge issued a statement Thursday urging President Obama to appoint a new chair "who will restore the agency's ability to protect the values so critical to our communications system and to our democracy."

The group credited Genachowski with several accomplishments, including his prevention of AT&T's takeover of T-Mobile, his support for satellite provider Dish Network's terrestrial wireless service and his work on limiting data roaming charge hikes and managing unlicensed airwaves.

However, Public Knowledge also described his term as "one of missed opportunities. He had the opportunity, but declined, to solidify the agency's authority and ability to protect consumers with regard to broadband -- the communications system of the present and future."

Genachowski "punted on" the issue of special access, which allows smaller carriers and businesses to lease the communication network lines that are owned by larger companies like AT&T and Verizon, it said.

Under his watch, "the enormous consolidation that has taken place in the broadband marketplace" continues to undermine competition, it said.

The FCC also approved Comcast's acquisition of NBCUniversal in 2011 and T-Mobile's merger with MetroPCS earlier this year.

"As a result, there is a real danger that the FCC will become a powerless and irrelevant agency as the nation's communications networks change."

Genachowski was top technology advisor during Obama's first presidential campaign. Like many of Obama's top administration officials who worked with the president at the Harvard Law Review, Genachowski worked as an editor there when Obama was its president.

The challenge for his successor as chairman? "To keep the agency focused on broadband and keep making decisions that drive economic growth and bring benefits to all Americans," Genachowski said.